if its the same as an 8hp, you need to gently tap the end cap about 15 degrees to one side....and i mean GENTLY!! then GENTLY tap the end cap out.....and again, be patient, and be GENTLE, those ears will break off very easily.
that's a 1994 model 9.9 if you want to look at diagrams at marineengine.com..also..google.. Leeroy's Ramblings..outboard motor related articles ..9.9/15 hp...it'll have a wealth of info including info on those seals